This supporting structure may be constituted, for example, by a vertical aluminum bar having a retaining groove of T-shaped section for receiving a plurality of fixing means disposed at different heights above the ground. Prior retaining systems are known which comprise:
a stack of retaining stages following one another in a stacking direction and each extending along a longitudinal direction and along a lateral direction;
each of said stages including retaining means for receivig one of said objects to be retained;
a first stage being provided with fixing means for fixing it to said supporting structure; and
each subsequent stage being provided with link means for linking it to the preceding stage.
In these prior systems, the means linking successive stages are constituted by screws. It therefore takes considerable time to build a stack, and a screwdriver must be available. A very wide range of fixing means are available for fixing the first stage to the supporting structure.
The aim of the present invention is to make stacking simpler and quicker than before, at least when the loads supported by the stack when in use remain moderate.